Student responses may shed light on who responds best to transcranial magnetic stimulation for depression

New findings from researchers at UCLA Health suggest that measuring changes in how pupils respond to light could help predict recovery from depression and personalize depression treatments. Transcranial magnetic stimulation (TMS) for major depressive disorder.

TMS is a safe, non-invasive therapy that uses magnetic fields to stimulate parts of the brain involved in mood regulation. Although TMS has been shown to be effective, not all patients respond well to this therapy. The ability to predict who will benefit the most could allow doctors to better customize and target treatments.

In two recent studies, UCLA scientists found that students’ response to light before treatment correlated with improvement in depressive symptoms during therapy. Pupil size reflects the activation of the autonomic nervous system, which controls involuntary functions and is negatively affected in people with depression.

The study first appeared in Journal of Affective Disorders, reported on the results of 51 patients who underwent daily TMS sessions. Before receiving treatment, researchers measured the patient’s baseline pupil constriction amplitude, or CA: the degree of pupil constriction when exposed to light. Pupil constriction is a sign of parasympathetic nervous system function.

The researchers found a significant association between baseline pupillary constriction amplitude and symptom improvement, suggesting that greater constriction amplitude at baseline was associated with better outcomes. In other words, people with larger pupil constrictions in response to light initially showed better symptom improvement than with full treatment.

The second study, appears in Brain stimulation, went further and compared patients treated for depression with one of two popular TMS protocols: 10 Hz stimulation and intermittent theta burst stimulation (iTBS). In 10 Hz stimulation, magnetic pulses are delivered at a fixed rate of 10 pulses per second or 10 Hz, a continuous and relatively high-frequency stimulation.

iTBS is a faster form of stimulation with bursts of three pulses at 50 Hz, repeated with short rests between bursts. This pattern is said to mimic the natural rhythms of certain brain activities.

The researchers found that people with slower pupil constriction had significantly improved depression after 10 sessions if they received iTBS instead of 10 Hz treatment.

“These results show that we can use a simple test on students to determine who is highly responsive,” said researcher Cole Citrenbaum, lead author of both studies. with electromagnetic stimulation of the brain to treat depression. TMS Clinical and Research Program at the Semel Institute for Neuroscience and Human Behavior at UCLA.

The researchers suggest that measuring pupillary response before initiating TMS may help guide treatment selection on an individual basis. “In addition, we can tailor the frequency of stimulation to each patient to maximize their benefit from treatment,” said Citrenbaum. This individualized approach can lead to better outcomes for patients.

“At the present time, about 65% of patients receive TMS treatment significantly improved their depression.” and Human Behavior at UCLA.

“Our goal is to help more than 85% of patients fully recover from depression. As we better understand the complex brain activity that causes depression, we move closer to matching patients with treatments that ensure their full recovery. Pupil testing can be a useful tool.” in achieving this goal.”

These studies add to the evidence for the benefits of biology-based personalization in the treatment of major depression. UCLA researchers plan further testing to confirm the value of pupillometry in optimizing transcranial magnetic stimulation.